脱式计算、(能简算的简算) 201×0.65-0.65 3.6×0.7×2.5 6.44×3.7+6.44×6.3 1.
1个回答

解题思路:(1)(3)运用乘法分配律简算;

(2)把3.6看作4×0.9,运用乘法交换律与结合律简算;

(4)运用乘法交换律与结合律简算.

(1)201×0.65-0.65,

=(201-1)×0.65,

=200×0.65,

=130;

(2)3.6×0.7×2.5,

=4×0.9×0.7×2.5,

=(0.9×0.7)×(2.5×4),

=0.63×10,

=6.3;

(3)6.44×3.7+6.44×6.3,

=6.44×(3.7+6.3),

=6.44×10,

=64.4;

(4)1.25×39.5×0.8,

=(1.25×0.8)×39.5,

=1×39.5,

=39.5.

点评:

本题考点: 小数四则混合运算;运算定律与简便运算.

考点点评: 完成本题,要注意分析式中数据,运用合适的简便方法计算.